Shaped charge weapons have a focus distance, determined by the shape of the penetrator cone. In the past RPGs used a inverted conical penetrator, (the innermost part of the cone turns inside out and becomes the leading edge of the penetration stream) which gives moderage penetration over a wide range of detonation distances. This was selected by the russian designers because the germans during wwii used "bazooka plates", thin steel plates to prematurely detonate shaped charge rounds at the wrong focus distance, which limited penetration effectiveness. Fender skirts are the modern expression of the bazooka plates.

Western penetrators have a more complex shape, and detonation at the correct distance is nearly guaranteed by the high quality and uniformity of the detonation mechanism. This gives superior performance (about 10 diameters of penetration) compared to russian weapons (about 6 diameters of penetration).

This indicates to me that either a new design RPG may be out there, or.....someone got hold of a western antitank weapon. Can we all say it together? FRANCE.

5
posted on 10/28/2003 11:54:16 PM PST
by donmeaker
(Bigamy is one wife too many. So is monogamy.)

Shaped charge weapons have a focus distance, determined by the shape of the penetrator cone.

And the diameter of the charge, which affects the required depth and thickness of the cone to achieve the Monroe Effect's focused blast. That can be counter productive to the aerodynamic shape required for effective flight, one reason why the WWII German Panzerfausts were short ranged, but very effective when they hit.

Additionally, the charge needs to be base detonated, though the noze fuze needs to be able to function even if it strikes the target at a less-than-ideal 90º angle. Typically, as in the Soviet PG-7 warhead or that of the M72 series US and British 66mm LAW rockets, that's accomplished with a piezoelectric crystal that provides a sufficient electrical charge to fire the charge's detonator when crushed into the target at flight speed. In the case of the RPG, the copper liner of the shaped charge is used as one electrical conductor to carry that electrical impulse for firing If the external body of the rocket is smashed into the charge liner, as when the rocket hits chail link fencing rather than solid plate, a short circuit of the firing circuit results and a dud round is the result. In practice, chainlink fencing will disable around 50% of the PG-7 rockets fired into it. M72 LAW rockets, being smaller, more often slip through, but are more often deflected, preventing a solid hit against the armor and thereby also resulting in a dud strike.

It could also be a variant of our own TOW missiles. Back in the Iran-Contra thing, TOW's were part of the shipment. Over the last 17 years, the Iranians may have developed their own version (or old TOW's found their way to the Soviets).

Suppose somebody built a rail-gun or coil-gun that worked outside the laboratory and launched a dense penetrator at ultra-high velocities...(?)

I'm thinking 20 km/s or higher....(?)

--Boris?

Or an APFSDS sabot round for their 2A42 30mm gun used on the BMP2 and BMP-3 Mech Infantry vehicles like the 25mm sabot rounds we have for the Bradley's Chain Gun, with performance somewhere between that of the US 25mm and the 30mm GAU-8 tank-killing Gatling Gun of the A10 *Warthog*.

There's a shoulder-fired 23mm Russian antitank rifle, too, a semirecoilless weapon something like an oversized M82A1 Barrett .50 caliber AMR. Maybe a really high performance round like the .50 Raufoos shaped charge has been developed for it, or maybe a light tripod-mounted 30mm version has been worked up....

I don't think we're quite to the point where a usable rail gun could be fielded in a package any smaller than roughly a 40-foot semitrailer truck or container, though it's certainly going to happen in the near future. But whether an electromagnetically accelerated projectile, a hypervelocity kinetic energy round, or an advanced small caliber chemical energy HEAT warhead, it's bad news for the crews in the Abrams...and worse news for those in Strykers.

It could also be a variant of our own TOW missiles. Back in the Iran-Contra thing, TOW's were part of the shipment. Over the last 17 years, the Iranians may have developed their own version (or old TOW's found their way to the Soviets).

Could be, though I think we'd have been at least generally familiar with the effects of one of our own warheads, even if reverse-engineered and upgraded [as we did with the Soviet SA-7 *Strella*] by a foreign source. The Russian Copy of the M72A2 LAW as their RPG-18 Mukha comes to mind....

But the Brits use the TOW in at least limited numbers as well, though they favour the MILAN for dismounted Infantry use. I wonder if they might have misplaced any new goodies from their boffins while they were in the area during Operation Telic.

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